4-phenoxycoumarins as herbicidal agents

ABSTRACT

There are provided methods to control monocotyledenous weed species in the presence of crops and particularly in the presence of cereal crops. Also provided are 4-(2,6-disubstituted-phenoxy)coumarin derivatives useful as herbicidal agents and methods to prepare same.

This is a divisional of application Ser. No. 08/515,846 filed on Oct. 10, 1995, now U.S. Pat. No. 5,681,968, which is a CIP of Ser. No. 08/279,579, filed Jul. 25, 1994, now U.S. Pat. No. 5,563,280.

BACKGROUND OF THE INVENTION

The selective control of weeds is a constant problem in crop production around the world. In particular the control of monocotyledenous weeds when growing in the presence of monocotyledenous crops such as cereal crops is burdensome. Not only do said weed species tend to proliferate under the same or similar cultivation conditions in which cereal crops flourish, but in addition, the very herbicidal agents which are most effective for controlling these weeds, also tend to cause harmful phytotoxic effects to cereal crop plants. Therefore, new effective methods for the selective control of unwanted monocotyledenous weeds in cereal crop production are continually sought.

It is an object of this invention to provide methods for the effective control of monocotyledenous weeds in the presence of crop plants, including monocotyledenous crop plants, without undue harm to said crop plants.

It is a further object of this invention to provide 4-(2,6-disubstituted-phenoxy)coumarin derivatives, useful as selective herbicides in crop production and particularly in cereal crop production.

It is an advantage of this invention that the 4-(2,6-disubstituted-phenoxy)coumarin derivatives are particularly effective for controlling grass and other monocotyledenous weeds under flooded paddy rice application conditions while having little or no phytotoxic effects on the rice crop.

SUMMARY OF THE INVENTION

The present invention relates to a method for the control of monocotyledenous annual, perennial and aquatic plant species which comprises applying to the soil or water containing the seeds or other propagating organs of said plant species a herbicidally effective amount of a compound of formula I ##STR1## wherein X and X are each independently halogen, C₁ -C₄ alkyl or C₂ -C₄ alkenyl;

W, Y and Z are each independently O or S;

R is any combination of from one to three H, halogen, C₁ -C₄ alkyl, C₃ -C₆ cycloalkyl, C₁ -C₄ haloalkyl or C₁ -C₄ alkoxy groups;

R₁ is any combination of from one to four H, halogen, OH, CN, NO₂, SH, C₁ -C₆ alkyl optionally substituted with one or more halogen or OR₂ groups, C₃ -C₆ cycloalkyl, C₁ -C₆ alkylthio, C₂ -C₆ alkenyl, C₂ -C₆ halo-alkenyl, C₂ -C₆ alkynyl, C₂ -C₆ haloalkynyl, OR₂, OCH₂ COOR₃, OCH₂ OR₄, OCOOR₅, OCONHR₆, OCOR₇, S(O)_(n) R₈, COR₉, CH(OR₁₀)₂, phenyl optionally substituted with one to three halogen, CN,

C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups, or benzyl optionally substituted with one to three halogen, CN, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl or C₁ -C₄ alkoxy groups;

R₂ is H, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₂ -C₆ alkenyl, C₂ -C₆ alkynyl, C₂ -C₆ haloalkenyl or C₂ -C₆ haloalkynyl;

R₃, R₄, R₅, R₆, and R₇ are each independently H, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₃ -C₆ cycloalkyl, phenyl optionally substituted with one to three halogen, CN, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups, or benzyl optionally substituted with one to three halogen, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl or C₁ -C₄ alkoxy groups;

R₈ is C₁ -C₄ alkyl, C₁ -C₄ haloalkyl or phenyl optionally substituted with one to three halogen, CN, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups;

R₉ is H, OH, C₁ -C₄ alkyl, C₁ -C₄ alkoxy, phenyl optionally substituted with one to three halogen, CN, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups, benzyl optionally substituted with one to three halogen, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups or NR₁₁ R₁₂ ;

R₁₀ is H, C₁ -C₄ alkyl or --(CH₂)_(m) --;

R₁₁ and R₁₂ are each independently H, C₁ -C₄ alkyl, C₂ -C₄ alkenyl or R₁₁ and R₁₂ may be taken together with the atoms to which they are attached to form a 5- or 6-membered ring optionally interrupted by oxygen;

n is an integer of 0, 1 or 2 and

m is an integer of 2 or 3.

The invention also relates to the selective control of monocotyledenous weed species in the presence of crops which comprises applying to the soil or water in which the seeds or propagating organs of the weed species are located and in which the crop has been planted or transplanted a herbicidally effective amount of a compound of formula I as described hereinabove.

The invention further relates to herbicidal compounds of formula I, compositions containing same, and a method to prepare said compounds.

DETAILED DESCRIPTION OF THE INVENTION

Crop production can be reduced by as much as 30% to 60% by the presence of persistent and pestiferous weed species. A particular weed problem in raising and harvesting a variety of crops, particularly cereal crops, is monocotyledenous weed species such as monochoria, saggitaria, sedges and grasses. This is a persistent problem in the production of cereals such as corn, wheat, barley, rice, rye and the like. Most particularly, the presence and proliferation of grass weeds such as barnyardgrass and watergrass in rice cultivation can significantly lower crop yields and quality. The problem is further complicated because, in general, those agents which control monocotyledenous plants inherently cause phytotoxic damage to cereal crops.

It has now been found that monocotyledenous, annual, perennial and aquatic, weed species such as monochoria, saggitaria, sedges and grasses are effectively controlled by the application of 4-phenoxycoumarin derivatives of formula I to the soil or water in which the seeds or propagating organs are located.

Surprisingly, said monocotyledenous weeds may be selectively controlled in the presence of cereal crops such as corn, wheat, barley, rice, rye and the like with little or no phytotoxic injury to said crops. Advantageously, 4-phenoxycoumarins of formula I may e applied preemergence to the monocotyledenous weeds and post-transplant to the rice crop seedlings under flooded paddy conditions to give effective weed control with little or no commensurate injury to the rice crop plants.

The 4-phenoxycoumarin derivatives of the invention which are useful as herbicidal agents are those compounds of formula I ##STR2## wherein X and X' are each independently halogen, C₁ -C₄ alkyl or C₂ -C₄ alkenyl;

W, Y and Z are each independently O or S;

R is any combination of from one to three H, halogen, C₁ -C₄ alkyl, C₁ -C₆ alkylthio, C₃ -C₆ cycloalkyl, C₁ -C₄ haloalkyl or C₁ -C₄ alkoxy groups;

R₁ is any combination of from one to four H, halogen, OH, CN, NO₂, SH, C₁ -C₆ alkyl optionally substituted with one or more halogen or OR₂ groups, C₃ -C₆ cycloalkyl, C₁ -C₆ alkylthio, C₂ -C₆ alkenyl, C₂ -C₆ haloalkenyl, C₂ -C₆ alkynyl, C₂ -C₆ haloalkynyl, OR₂, OCH₂ COOR₃, OCH₂ OR₄, OCOOR₅, OCONHR₆, OCOR₇, S(O)_(n) R₈, COR₉, CH(OR₁₀)₂, phenyl optionally substituted with one to three halogen, CN, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups, or benzyl optionally substituted with one to three halogen, CN, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl or C₁ -C₄ alkoxy groups;

R₂ is H, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₂ -C₆ alkenyl, C₂ -C₆ alkynyl, C₂ -C₆ haloalkenyl or C₂ -C₆ haloalkynyl;

R₃, R₄, R₅, R₆ and R₇ are each independently H, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₃ -C₆ cycloalkyl, phenyl optionally substituted with one to three halogen, CN, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups, or benzyl optionally substituted with one to three halogen, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl or C₁ -C₄ alkoxy groups;

R₈ is C₁ -C₄ alkyl, C₁ -C₄ haloalkyl or phenyl optionally substituted with one to three halogen, CN, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups;

R₉ is H, OH, C₁ -C₄ alkyl, C₁ -C₄ alkoxy, phenyl optionally substituted with one to three halogen, CN, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups, benzyl optionally substituted with one to three halogen, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups or NR₁₁ R₁₂ ;

R₁₀ is H, C₁ -C₄ alkyl or --(CH₂)_(m) --;

R₁₁ and R₁₂ are each independently H, C₁ -C₄ alkyl, C₂ -C₄ alkenyl or R₁₁ and R₁₂ may be taken together with the atoms to which they are attached to form a 5- or 6-membered ring optionally interrupted by oxygen;

n is an integer of 0, 1 or 2 and

m is an integer of 2 or 3.

It is understood that R and R₁ represent substituents on the phenyl ring in positions 3, 4 and 5 (in the case of R) and on the fused benzene ring in positions 5, 6, 7 and 8 (in the case of R₁). In each instance the aromatic ring may range from being fully substituted to being fully unsubstituted (in the case of R₁) or disubstituted by X and X' (in the case of R). When the phenyl ring is disubstituted with X and X', then R is designated H. When the fused benzene ring position of the 4-phenoxycoumarin of formula I is fully unsubstituted, then R₁ is designated H.

The term haloalkyl designates an alkyl group, C_(n) H_(2n+1), containing from one halogen atom to 2n+1 halogen atoms. Halogen atoms are Cl, Br, F or I.

Preferred compounds of formula I are those wherein X and X' are each independently Cl, Br, or CH₃ and W, Y and Z are O. More preferred compounds are those wherein X and X' are each independently Cl, Br or CH₃ ; W, Y and Z are O; P is H and R₁ is one, two or three halogen, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy, C₁ -C₄ haloalkoxy or NO₂ groups. Particularly preferred compounds are those wherein X and X' are each independently Cl, Br or CH₃ ; W, Y and Z are O; R is H and R₁ is 5-C₁ -C₄ alkyl, 5-halogen, 5-C₁ -C₄ haloalkyl or 5-NO₂.

The 4-(2,6-disubstituted-phenoxy)coumarin compounds of formula I may be prepared from readily available 2-hydroxyacetophenones of formula III or their salicylic acid precursors of formula II. The formula II acid may be converted to the corresponding acetophenone of formula III in the presence of methyl lithium using standard literature procedures such as that described by Heimark et al in the Journal of Labelled Compounds and Radiopharmaceuticals, 1986, Vol. 23, No. 2. The formula III acetophenone may be reacted with ethyl carbonate in the presence of at least 2 molar equivalents of a base such as sodium hydride to give the 4-hydroxycoumarin of formula IV. Said hydroxycoumarin may then be converted to the corresponding 4-chlorocoumarin derivative of formula V, using standard procedures such as POCl₃ plus an amine scavenger. The formula V chlorocoumarin is then reacted with a 2,6-disubstituted-phenol or thiophenol of formula VI to give the desired formula I product wherein Y is oxygen (formula Ia). To obtain those formula I products wherein Y is sulfur (Ib), the coumarin of Ia may be reacted with Lawesson's reagent or P₂ S₅. The reaction scheme is shown in Flow Diagram I. ##STR3##

Alternatively, the formula II salicylic acid may be converted to the corresponding formula VII acid chloride. The acid chloride may be treated with ethyl malonate in the presence of a base as described in Journal of Medicinal Chemistry, 1975, Vol. 18, No. 4, pp. 391-394 by D. R. Buckle et al, to form an intermediate which is decarboxethoxylated by heating, optionally in the presence of a solvent, to afford the desired 4-hydroxycoumarin of formula IV. The formula IV hydroxycoumarin may be converted to 4-(2,6-disubstituted-phenoxy)coumarin compounds of formula I as shown hereinabove in Flow Diagram I. The reaction sequence is illustrated in Flow Diagram II. ##STR4##

The 4-(2,6-disubstituted phenoxy)coumarin herbicidal agents of formula I may also be effectively prepared from phenols of formula VIII by treatment with dimethyl acetylenedicarboxylate as described by H. Cairns, et al in the Journal of Medicinal Chemistry, 1972, Vol. 15, No. 6, pp. 583-589, to give the formula IX fumaric acid. Surprisingly, treatment of the formula IX fumaric acid with a mixture of phosphorous pentoxide and methane sulfonic acid affords the formula X chromone-2-carboxylic acid in high yield. The formula X intermediate may then be converted to the formula V chlorocoumarin by treatment with thionyl chloride in the presence of a catalytic amount of dimethyl formamide as described by V. A. Zagorevskii and E. K. Orlova in Zhurnal Obschei Khimii, Vol. 33, No. 6, 1963, pp. 1857-1863. The thus-prepared 4-chlorocoumarin may be employed to give the desired 4-(2,6-disubstituted phenoxy)coumarins of formula I as described hereinabove in Flow Diagram I. The reaction sequence is illustrated in Flow Diagram III. ##STR5##

The 4-phenoxycoumarin compounds of the present invention are those compounds of formula I wherein X, X', W, Y, R and R₁ are as described hereinabove with the proviso that at least one of R₁ must be other than H. Said compounds are effective herbicidal agents useful for the control of a variety of monocotyledenous annual and perennial weed species. Moreover, these compounds are effective for the control of weeds indigenous to both dry land and wet land areas. Effective control may be obtained with application rates of about 0.006 kg/ha to 4.0 kg/ha, preferably about 0.06 kg/ha to 2.0 kg/ha. It is, of course, clear that rates above 4.0 kg/ha may be used to effectively control undesirable monocotyledenous weed species; however, rates of application of herbicide above the required effective level should be avoided since application of excessive amounts of herbicide is costly and serves no useful function in the environment.

Surprisingly, it has been found that the formula I phenoxycoumarin compounds of the invention are selective herbicides, useful in crop production.

In particular, the formula I compounds are effective for controlling pestiferous monocotyledenous weeds such as grasses, sedges, monochoria and saggitaria in the presence of cereal crop plants such as corn, wheat, rye, barley, rice and the like. More particularly, the formula I compounds are especially valuable for controlling grass weeds in the presence of transplanted rice plants under flooded paddy conditions.

In actual agronomic practice, the compounds of the invention are applied in the form of a composition comprising an agronomically acceptable solid or liquid carrier and an herbicidally effective amount of a formula I phenoxycoumarin compound. For example, application may be in the form of liquid compositions such as suspension concentrates, aqueous concentrates, emulsifiable concentrates, concentrated emulsions and the like or in the form of solid compositions such as wettable powders, dispersible granulars, granular formulations, dusts and the like. It is contemplated the compounds of the invention be applied in combination with other pesticides either sequentially or concurrently as a tank mixture or as a single combination composition. In particular the combination application of a formula I phenoxycoumarin with a co-herbicide such as a sulfamoylurea, sulfonylurea, dinitroaniline, imidazolinone, thiocarbamate, azolopyrimidine sulfonamide, α-haloacetamide and the like. Of particular interest are combinations comprising a formula I phenoxycoumarin and a sulfamoylurea, a dinitroaniline, a sulfonylurea, or an imidazolinone. While not required, the combination composition comprising a formula I compound and a co-herbicide may also comprise other components, for example, fertilizers, inert formulation aides such as surfactants, emulsifiers, defoamers, dyes, extenders and the like.

For a more clear understanding of the invention, specific examples thereof are set forth below. The invention described and claimed herein is not to be limited in scope by these merely illustrative examples. Indeed, various modifications of the invention in addition to those exemplified and described herein will become apparent to those skilled in the art from the following examples and the foregoing description. Such modifications are also intended to fall within the scope of the appended claims. The terms ¹ H, ¹³ C, ¹⁹ FNMR designate proton, carbon and fluorine nuclear magnetic resonance spectroscopy, respectively. IR designates infrared spectroscopy and HPLC designates high performance liquid chromatography.

EXAMPLE 1 Preparation of 2-hydroxy-3-methoxyacetophenone ##STR6##

A mixture of 3-methoxysalicylic acid (4.0g, 24 mmole) in tetrahydrofuran, under nitrogen, is treated dropwise with methyl lithium (56 mL of 1.4M solution in ether, 78.4 mmole) at a rate sufficient to maintain reflux temperature. The reaction mixture is stirred at reflux temperature for 17 hours, cooled to room temperature and poured over a mixture of brine, ice and 6N HCl. The resultant mixture is extracted with ethyl acetate. The organic extracts are combined, washed with brine, dried over Na₂ SO₄ and filtered. The filtrate is concentrated in vacuo to give a dark orange residue which is taken up in 1:2 ethyl acetate: hexane, filtered through a silica gel plug and re-evaporated to give a residue. This residue is crystallized from cyclohexane to give the title product as yellow needles, 2.08 g (53% yield), mp 49°-510° C., identified by HPLC, ¹ HNMR and mass spectral analyses.

EXAMPLE 2 Preparation of 8-methoxy coumarin ##STR7##

A stirred mixture of NaH(0.58 g 60% NaH, 14.5 mmole) and ethyl carbonate (2.84 g, 24 mmole) in chloroform, under N₂ is treated dropwise with a solution of 2-hydroxy-3-methoxyacetophenone (0.80 g, 4.8 mmole) in chloroform, heated at reflux temperature for 40 hours, cooled to room temperature, treated with about 45 mL 1N NaOH and stirred vigorously for 24 h, The phases are separated and the aqueous phase is acidified with 6N HCl. The resultant precipitate is filtered, washed with water and dried to give the title product as a white solid, 0.88 g (96% yield), identified by ¹ HNMR analysis.

EXAMPLE 3 Preparation of 4-chloro-6-methoxycoumarin ##STR8##

A stirred mixture of 4-hydroxy-6-methoxycoumarin (116 g, 0.603 mole) and POCl₃ (462.29 g, 3.015 mole) in toluene is treated dropwise with tri-n-butylamine (250 mL, 1.73 mole) at 25° C., heated at 100°-110° C. and monitored by HPLC analysis. When the reaction is complete, the mixture is cooled to room temperature, poured over ice, stirred mechanically for about 2 hours and filtered. The filtercake is washed with water and toluene, dissolved in methylene chloride and filtered through diatomnaceous earth. The methylene chloride filtrate is concentrated and treated with a mixture of dimethylformamide and acetonitrile to afford crystallization. The mixture is filtered to give the title product, 81.7 g, (64% yield) identified by HPLC analysis.

EXAMPLE 4 Preparation of 4-(2,6-dichlorophenoxy)-6-methoxycoumarin ##STR9##

A stirred mixture of 4-chloro-6-methoxycoumarin (1.0 g, 4.75 mmole), 2,6-dichlorophenol (0.85 g, 5.22 mmole) and K₂ CO₃ (0.98 g, 7.12 mmole) in acetonitrile, under N₂, is heated at reflux temperature for 16 hours, cooled to room temperature and poured into ice water. This mixture is extracted several times with ether. The extracts are combined and concentrated in vacuo to give a tan solid residue. The residue is crystallized from ethyl acetate/hexane to afford the title product as tan crystals, 1.17 g (73% yield), mp 170°-171° C., identified by IR, ¹ HNMR, ¹³ CNMR, and mass spectral analyses.

EXAMPLE 5 Preparation of 4-(2-6-dichlorophenoxy)-6-hydroxycoumarin ##STR10##

A solution of 4-(2,6-dichlorophenoxy)-6-methoxycoumarin (25 g, 0.074 mol) in methylene chloride, under N₂, is treated dropwise with 296 mL of a 1.0M solution of BBr₃ in methylene chloride at -70° C. When addition is complete, the dry ice/acetone cooling is removed and the reaction is allowed to come to room temperature over a 16 hour period. The reaction mixture is diluted with additional methylene chloride, poured into ice water with mechanical stirring and filtered to give a pale yellow solid filtercake. The solid is air-dried and crystallized from dimethylformamide/acetonitrile/water (1:1:0.1) to afford the title product as white crystals, 19.7 g (86% yield), mp>250° C. identified by ¹ HNMR analysis.

EXAMPLE 6 Preparation of 4-(2,6-dichlorophenoxy)-6-(difluoromethoxy)coumarin ##STR11##

A stirred suspension of 4-(2,6-dichlorophenoxy)-6-hydroxycoumarin (1.3 g, 3.71 mmole) in acetone is bubbled through with chlorodifluoromethyl at room temperature, under N₂, for about 30-45 minutes, cooled to 5°-10° C., treated with 50% NaOH solution (2.4 g, 1.2 g NaOH, 29.7 mmole NaOH), stirred or 2 hours at room temperature and filtered. The solid filtercake is washed with methylene chloride and crystallized from acetonitrile/methanol/water to afford the title product as a white solid, 0.95 g (69% yield), mp 145°-148° C., identified IR, ¹ HNMR, ¹⁹ FNMR, ¹³ CNMR, and mass spectral analyses.

EXAMPLE 7 Preparation of 4-hydroxy-8-nitrocoumarin ##STR12##

A solution of NaH (6.94 g, 0.291 mole) in dimethoxyethane is cooled using dry ice/acetone cooling, treated dropwise with diethyl malonate (46.6 g, 0.29 mole), allowed to warm to 0° C., treated dropwise with a solution of 3-nitrosalicylyl chloride (19.5 g, 0.10 mole) in dimethoxyethane, allowed to warm to room temperature, stirred for 3 hours at room temperature, heated at 60° C. until reaction is complete by HPLC analysis, cooled to room temperature, poured onto a mixture of ice water and methylene chloride and stirred for about 0.5 hour. The phases are separated, the aqueous phase is acidified with 50% HCl to pH 5 and filtered. The filtercake is dispersed in acetic acid, heated and filtered. This filtercake is air-dried and 8.6 g is dispersed in dimethyl sulfoxide, heated at 100° C. for about 2 hours, cooled to room temperature, poured onto ice water and filtered. The solid is taken up in acetonitrile, filtered hot, cooled and filtered to give the title product, mp 242°-245° C., identified by IR, ¹ HNMR and mass spectral analyses.

EXAMPLE 8 Preparation of 4-(2,6-dichlorophenoxy)-6-methoxythionocoumarin ##STR13##

A mixture of 4-(2,6-dichlorophenoxy)-6-methoxycoumarin (0.409 g 1.2 mmol) and Lawesson's Reagent¹ (0.53 g, 1.3 mmol) in dioxane is heated at reflux temperature, stirred for about 4 hours, cooled to room temperature, stirred at room temperature for 16 hours and filtered. The filtercake is washed with petroleum ether and air-dried to give the title product as a yellow solid, 0.28 g (57% yield), mp 231°-232° C., identified by ¹ HNMR, ¹³ CNMR and mass spectral analyses.

EXAMPLES 9-15 Preparation of 4-phenoxythionocoumarin derivatives ##STR14##

Using essentially the same procedure described in Example 8 and substituting the appropriate 4-phenoxycoumarin substrate, the following compounds are obtained.

                  TABLE I                                                          ______________________________________                                          ##STR15##                                                                     Example                                                                        No.       X     X'        R   W       R.sub.1                                  ______________________________________                                         9         Cl    Cl        H   O       5-OH                                     10        Br    Br        H   O       7-OCH.sub.3                              11        Cl    Cl        H   O       7-OCH.sub.3                              12        Cl    Cl        H   O       6,7-di-OCH.sub.3                         13        Cl    Cl        H   O       7-NO.sub.2                               14        Cl    Cl        H   O       5-OC.sub.2 H.sub.5                       15        Cl    Cl        H   O       5-OCHF.sub.2                             ______________________________________                                    

EXAMPLE 16 Preparation of 4-(2,6-dichlorophenoxy)-6-(N-methylcarbamoyl)coumarin ##STR16##

A solution of 4-(2,6-dichlorophenoxy)-6-hydroxycoumarin (0.5 g, 1.55 mmole) in dimethyl formamide, under nitrogen, at room temperature is treated with triethylamine (0.7 mL, 5 mmole), then treated with CH₃ NCO (0.5 mL, 5.5 mmole) and allowed to stir at room temperature for about 1 hour. When the reaction is complete by HPLC analysis, the reaction mixture is poured onto water and extracted with methylene chloride. The extracts are concentrated in vacuo to give a residue. The residue is crystallized from methylene chloride/hexane to afford the title product as white crystals, 0.38₂ (71% yield), mp 292°-299° C., identified by ¹ HNMR, ¹³ CNMR and IR analyses.

EXAMPLE 17 Preparation of 4-(2,6-dichlorophenoxy)-6-(methoxymethyloxy)coumarin ##STR17##

A mixture of 4-(2,8-dichlorophenoxy)-6-hydroxycoumarin (1.2 g, 3.2 mmol), dimethoxymethane (0.565 g, 7.4 mmole), POCl₃ (0.74 g, 4.8 mmole) and dimethylformamide (0.43 g, 5.94 mmole) in toluene is heated at 90°-100° C. for 4 hours, cooled to room temperature, poured onto ice water and filtered. The filtercake is dried and recrystallized from acetonitrile/water to afford the title product, 0.45 g (38% yield), mp 302°-305° C. (dec), identified by ¹ HNMR, ¹³ CNMR and IR, analyses.

EXAMPLE 18 Preparation of 2-hydroxy-4,5-dimethoxyacetophenone ##STR18##

A solution of 3,4-dimethoxyphenol (0.50 g, 3.24 mmole) in acetic acid is treated with boron trifluoride etherate (1.20 ml, 9.72 mmole) at 25° C., heated at reflux temperature until reaction is complete by thin layer chromatographic analysis, cooled to room temperature and poured onto ice water. The resultant mixture is filtered, the filtercake is washed with water and ether and dried in vacuo to give the title product as an orange powder, 0.64 g (100% yield), identified by ¹ HNMR.

EXAMPLE 19 Preparation of 2- 4-(trifluoromethoxy)phenoxy!fumaric ##STR19##

A mixture of 4-(trifluoromethoxy)phenol (2.75 g, 12.5 mmole) and dimethyl acetylene dicarboxylate (1.69 ml, 13.7 mmole) in dioxane is treated with benzyltrimethylammonium hydroxide (0.15 ml, 40% aqueous) at room temperature under a nitrogen atmosphere, heated to 90°-95° C. (condensation complete by thin layer chromatographic analysis) cooled to 40° C., treated with sodium hydroxide (10 ml, 20% aqueous), heated at 90° C. for 1 hour and cooled to room temperature. The reaction mixture is treated with 10% aqueous HCl to pH 7 and filtered. The filtrate is acidified to about pH 1 with HCl to afford a yellow precipitate. The solid is filtered and dried to give the title product, 2.56 g (70% yield), mp 208°-210° C., identified by ¹ H, ¹³ C and ¹⁹ FNMR, mass spectral and elemental analyses.

EXAMPLE 20 Preparation of 6-(trifluoromethoxy)chromone-2-carboxylic acid ##STR20##

A solution of phosphorous pentoxide (1.17 g, 8.21 mmole) in methanesulfonic acid (14.38 g) is treated with 2- 4-(trifluoromethoxy)phenoxy!fumaric acid (2.00 g, 6.85 mmole), stirred for 16-18 hours at ambient temperatures and for 7 hours at 70° C., cooled to room temperature and poured onto ice. The resultant mixture is filtered and the filtercake is dried to afford the title product, 1.75 g, (93% yield), mp 192°-194° C., identified by ¹ H and ¹³ CNMR, IR, mass spectral and elemental analyses.

EXAMPLE 21 Preparation of 4-chloro-6-(trifluoromethoxy)coumarin ##STR21##

A stirred mixture of 6-(trifluoromethoxy)chromone-2-carboxylic acid (1.50 g, 5.47 mmole) in thionyl chloride (6.0 ml) is treated with 1 drop of dimethyl formamide (DMF), heated at reflux temperature for 6 hours, cooled to room temperature and concentrated in vacuo. The residue is dispersed in toluene, treated with a saturated NaHCO₃ solution and stirred until neutralized. The phases are separated and the toluene phase is concentrated in vacuo. The resultant residue is purified in acetonitrile and methylene chloride to give the title product, 1.04 g, (72% yield), mp 85°-87° C., identified by ¹ H, ¹³ C and ¹⁹ FNMR, IR, mass spectral and elemental analyses.

EXAMPLE 22-95 Preparation of 4-(2,6-substituted-phenoxy)coumarin derivatives

Using essentially the same procedures described in Examples 1 through 21, the following 4-(2,6-disubstituted-phenoxy)coumarin derivatives shown in Table II are obtained.

                                      TABLE II                                     __________________________________________________________________________      ##STR22##                                                                     Example                                                                        No.  X    X'     R     W Y R.sub.1    mp °C.                            __________________________________________________________________________     22   Cl   Cl     H     O O H          159                                      23   F    F      H     O O H          195.6                                    24   Br   Br     H     O O H          162-170                                  25   CH.sub.3                                                                            CH.sub.3                                                                              H     O O H          163-164                                  26   F    OCH.sub.3                                                                             H     O O H          145-146                                  27   F    NO.sub.2                                                                              H     O O H          203-205                                  28   OCH.sub.3                                                                           OCH.sub.3                                                                             H     O O H          175                                      29   Cl   Cl     H     O O 6-(2Cl,4CF.sub.3,6F-C.sub.6 H.sub.2)                                                      155-157                                  30   Cl   Cl     H     O O 6-CH.sub.3 191-192                                  31   Br   Br     H     O O 6-OCH.sub.3                                                                               174-175                                  32   Br   Br     H     O O 6-CH.sub.3 182-183                                  33   Cl   Cl     H     O O 6-(OCONHC.sub.2 H.sub.5)                                                                  220-221                                  34   OCH.sub.3                                                                           OCH.sub.3                                                                             H     O O 6-OCH3     206-208                                  35   Cl   Cl     H     O O 7-OCH3     165-168                                  36   OCH.sub.3                                                                           OCH.sub.3                                                                             H     O O 7-OCH3     205.5-207                                37   OCH.sub.3                                                                           OCH.sub.3                                                                             H     O O 5-OCH3     186.5-188.5                              38   Cl   Cl     H     O O 7-(OCH.sub.2 CHCH.sub.2)                                                                  185.5-182                                39   Cl   Cl     H     O O 5-(OCH.sub.2 CHCH.sub.2)                                                                  156.5-158.5                              40   Cl   Cl     H     O O 5-(OCH.sub.2 COOCH)                                                                       161.2-162.6                              41   Cl   Cl     H     O O 6-(OCH.sub.2 COOCH)                                                                       135-136                                  42   Cl   Cl     H     O O 6-(OCH.sub.2 CHCH.sub.2)                                                                  145-146                                  43   Cl   Cl     H     O O 6-(OCH.sub.2 CCH)                                                                         153                                      44   Cl   Cl     H     O O 6-(OCH.sub.2 CH.sub.2 CFCF.sub.2)                                                         146                                      45   CI   Cl     H     O O 6-OCH(CH.sub.3).sub.2                                                                     141                                      46   Cl   Cl     H     O O 6-OCH(CH.sub.3)C.sub.2 H.sub.5                                                            138                                      47   Cl   Cl     H     S O 6-OCH.sub.3                                                                               216-217                                  48   Cl   Cl     H     O O 6-OSO.sub.2 CF.sub.3                                                                      137                                      49   Br   Br     H     O O 6-F        165                                      50   Cl   Cl     H     O O 6-C.sub.2 H.sub.5                                                                         184                                      51   Cl   Cl     H     O O 6-F        183                                      52   Cl   Cl     H     S O 6-F        168                                      53   Cl   Cl     H     S O 6-C.sub.2 H.sub.5                                                                         182                                      54   Cl   Cl     4-Cl  O O 6,7-di-CH.sub.3                                                                           264                                      55   Br   Br     H     O O 6,7-di-OCH.sub.3                                                                          191                                      56   Cl   Cl     4-F   O O 6-OCH.sub.3                                                                               217                                      57   Cl   Cl     H     O O 6-Cl       204                                      58   Br   Br     H     O O 6-Cl       188                                      59   Cl   Cl     H     S O 6-Cl       214                                      60   Cl   Cl     4-Cl  O O 6-OCH.sub.3                                                                               196                                      61   Cl   Cl     4-F   O O 6,7-di-CH.sub.3                                                                           255                                      62   Cl   Cl     H     O O 6-OCH.sub.2 CHF.sub.2                                                                     167                                      63   Cl   Cl     H     O O 6,7-di-CH.sub.3                                                                           212                                      64   Cl   Cl     H     S O 6,7-di-CH.sub.3                                                                           246                                      65   Cl   CI     H     O O 6,7-di-OCH.sub.3                                                                          191                                      66   Cl   Cl     H     S O 6,7-di-OCH.sub.3                                                                          172                                      67   Cl   Cl     H     O O 6,8-di-Cl  206                                      68   Cl   Cl     H     S O H          212                                      69   Br   Br     H     O O 6-C.sub.2 H.sub.5                                                                         159                                      70   Br   Br     H     O O 6,7-di-CH.sub.3                                                                           210                                      71   Br   Br     H     O O 6,8-di-Cl  218                                      72   Cl   Cl     4-F   O O 6-F        187                                      73   Cl   Cl     4-Cl  O O 6-F        208                                      74   Cl   Cl     4-F   O O 6,7-di-OCH.sub.3                                                                          205                                      75   Cl   Cl     4-Cl  O O 6-Cl       221                                      76   Cl   Cl     4-F   O O 6-Cl       200                                      77   Cl   Cl     H     O O 6-OC.sub.2 H.sub.5                                                                        162                                      78   F    F      3,4,5-tri-F                                                                          O O 6-F        173                                      79   Br   Br     4-CH.sub.3                                                                           O O 6,7-di-OCH.sub.3                                                                          154                                      80   Cl   Cl     H     O O 6-OCH.sub.2 C.sub.6 H.sub.4 OCF.sub.3 -p                                                  129                                      81   Br   Br     4-F   O O 6-OCH.sub.3                                                                               200                                      82   Br   Br     4-Br  O O 6-OCH.sub.3                                                                               195-197                                  83   Cl   Cl     3-Cl  O O 6-OCH.sub.3                                                                               218-220                                  84   F    F      H     O O 6-OCH.sub.3                                                                               213-214                                  85   Cl   Cl     H     O O 6-CN       249-250                                  86   Cl   Cl     H     O O 5,6,7-tri-OCH.sub.3                                                                       169-170                                  87   Cl   Cl     H     O O 5-OCH.sub.3                                                                               203.6-207.5                              88   Cl   Cl     H     O O 7-OH       263-264.5                                89   Cl   Cl     H     O O 5-OH       250-256                                  90   Cl   Cl     H     S O 5-OCH.sub.3                                                                               204-205                                  91   Br   Br     H     O O 5-OCH.sub.3                                                                               201-203                                  92   Cl   Cl     H     S O 8-OCH.sub.3                                                                               183-185                                  93   Br   Br     H     O O 8-OCH.sub.3                                                                               157                                      94   Cl   Cl     H     O O 8-OCH.sub.3                                                                               142-144                                  95   Br   Br     H     O O 5,6,7-tri-OCH.sub.3                                                                       179-181                                  99   Br   Br     H     O O 6-OH       210                                      100  Cl   Cl     H     O O 6-I        266-267                                  101  Br   Br     H     O O 6-OCHF.sub.2                                                                              151-152                                  102  Cl   Cl     H     O O 8-OCHF.sub.2                                                                              198-201                                  103  Br   Br     H     O O 8-OCHF.sub.2                                                                              181-183                                  104  Cl   Cl     H     O O 6-CH.sub.2 OCH.sub.3                                                                      158                                      105  Br   Br     H     O O 8-OH       227                                      106  Cl   Cl     H     O O 8-OH       252                                      107  CH.sub.3                                                                            CH.sub.2 CHCH.sub.2                                                                   H     O O 6-OCH.sub.3                                                                               88-90                                    108  CH(CH.sub.3).sub.2                                                                  CH(CH.sub.3).sub.2                                                                    H     O O 6-OCH.sub.3                                                                               129-131                                  109  CH.sub.3                                                                            CH.sub.3                                                                              H     O O 6-OCH.sub.3                                                                               192-193                                  110  Cl   Cl     H     O O 6-OCF.sub.3                                                                               172-175                                  111  Cl   Cl     H     O O 6-CF.sub.3 181-183                                  112  Br   Br     H     O O 6-CH.sub.2 Br                                                                             220                                      113  Cl   Cl     H     O O 6-CHO      200                                      114  CH.sub.3                                                                            C(CH.sub.3)                                                                           H     O O 6-OCH.sub.3                                                                               148-151                                  115  Cl   Cl     H     O O 6-C.sub.6 H.sub.5                                                                         146-152                                  116  Cl   Cl     H     O O 6-COOH     305                                      117  Br   Br     H     O O 6-CHO      185-197                                  118  Cl   Cl     H     O O 6-OCH.sub.2 CH.sub.2 OC.sub.2 H.sub.5                                                     89-91                                    119  Cl   Cl     H     O O 6-SCH.sub.3                                                                               168-170                                  120  Cl   CH.sub.3                                                                              H     O O 6-OCH.sub.3                                                                               192                                      121  Cl   CH.sub.3                                                                              H     O O 6,7-di-OCH.sub.3                                                                          141                                      122  Cl   CH.sub.3                                                                              H     O O 6,7-di-OCH.sub.3                                                                          172-173                                  123  Cl   CH.sub.3                                                                              H     O O 6-CH.sub.3 186                                      124  Cl   CH.sub.3                                                                              H     O O 6-C.sub.2 H.sub.5                                                                         165-166                                  125  Cl   CH.sub.3                                                                              H     O O 8-OCH.sub.3                                                                               157-158                                  126  CH.sub.3                                                                            CH.sub.3                                                                              H     O O 8-OCH.sub.3                                                                               142-143                                  127  Cl   Cl     H     O O 6,7-di-OH  >300                                     128  CH.sub.3                                                                            n-C.sub.3 H.sub.7                                                                     H     O O 6-OCH.sub.3                                                                               --                                       129  CH.sub.3                                                                            CH.sub.3                                                                              H     O O 6-CF.sub.3 193-194                                  130  CH.sub.3                                                                            CH.sub.3                                                                              H     O O 6-OCF.sub.3                                                                               162-164                                  131  Cl   CH.sub.3                                                                              H     O O 8-CF.sub.3 205-206                                  132  Br   Br     3,5-di-OCH.sub.3                                                                     O O 6-OCH.sub.3                                                                               233-234                                  133  Cl   CH.sub.3                                                                              H     O O 5,6,7-tri-OCH.sub.3                                                                       143-144                                  134  I    I      4-I   O O 6-OCH.sub.3                                                                               202-203                                  135  Cl   Cl     H     O O 8-CF.sub.3 217-218                                  136  Cl   CH.sub.3                                                                              H     O O 5-OCH.sub.3                                                                               172-173                                  137  Cl   Cl     H     O O 5-CF.sub.3 159-160                                  138  Br   Br     H     O O 5-CF.sub.3 179-189                                  139  Cl   CH.sub.3                                                                              H     O O 5-CF.sub.3 157-159                                  140  Cl   CH.sub.3                                                                              H     O O 6-Cl,7-OCH.sub.3                                                                          167-168                                  141  Br   CH.sub.3                                                                              H     O O 6-OCH.sub.3                                                                               180-181                                  142  Cl   Cl     H     O O 6-C CH     220-224                                  143  Cl   CH.sub.3                                                                              H     O O 8-CH.sub.3 174-175                                  144  Cl   Cl     H     O O 7-OCHF.sub.2                                                                              158-160                                  145  Cl   CH.sub.3                                                                              H     O O 6-OCHF.sub.2                                                                              158-161                                  146  Cl   Cl     H     O O 7-CF.sub.3 180-181                                  147  Cl   CH.sub.3                                                                              H     O O 7-CF.sub.3 146-148                                  148  Cl   CH.sub.3                                                                              H     O O 7,8-di-OCH.sub.3                                                                          179-181.5                                149  Cl   Cl     H     O O 5-OCH(CH.sub.3).sub.2                                                                     158.5-162                                150  Cl   Cl     H     O O 5-OC.sub.2 H.sub.5                                                                        152.5-155                                151  Cl   Cl     H     O O 5-OCHF.sub.2                                                                              178.3-180                                152  Cl   Cl     H     O O 5-OCH.sub.3,6-Cl                                                                          176-178                                  153  Cl   Cl     H     O O 8-Cl       206-208                                  154  Cl   Cl     H     O O 5-OCOCH.sub.3                                                                             130-133                                  155  Cl   CH.sub.3                                                                              H     O O 5-Cl       135-136                                  156  Br   Br     H     O O 5-Cl       155-156                                  157  Cl   Cl     H     O O 5-Cl       157-158                                  158  Cl   Cl     H     O O 5-OCH.sub.3,8-Cl                                                                          213-215.5                                159  Cl   CH.sub.3                                                                              H     O O 5-CH.sub.3,8-Cl                                                                           175-176                                  160  Cl   Cl     H     O O 5-CH.sub.3,8-Cl                                                                           166-167                                  161  Cl   Cl     H     O O 5-OCOC(CH.sub.3).sub.3                                                                    139-141                                  162  Br   Br     H     O O 5-OCOCH.sub.3                                                                             220-223                                  163  Br   Br     H     O O 5-OCOC(CH.sub.3).sub.3                                                                    218.3-220                                164  Cl   Cl     H     O O 7-OCOCH.sub.3                                                                             182-183.5                                165  Cl   Cl     H     O O 7-OCOC(CH.sub.3).sub.3                                                                    135-137                                  166  Cl   Cl     H     O O 8-OCOCH.sub.3                                                                             161-163                                  167  Cl   Cl     H     O O 8-OCOC(CH.sub.3).sub.3                                                                    144-146                                  168  Cl   Cl     H     O O 5-F        146-147                                  169  Cl   CH.sub.3                                                                              H     O O 5-F        137-138                                  170  Cl   Cl     H     O O 5-CH.sub.3 129-130                                  171  Cl   CH.sub.3                                                                              H     O O 5-CH.sub.3 118-119                                  172  Cl   Cl     H     O O 5,7-di-Cl  205-207                                  173  Br   Br     H     O O 5,7-di-Cl  208-209                                  174  Cl   CH.sub.3                                                                              H     O O 5,7-di-Cl  158-160                                  175  Cl   Cl     H     O O 6,7-di-Cl  195-196                                  176  Cl   Cl     H     O O 5,6-di-Cl  193-195                                  177  Cl   CH.sub.3                                                                              H     O O 6,7-di-Cl  210-212                                  178  Br   Br     H     O O 6,7-di-CH.sub.3                                                                           155-156                                  179  Br   Br     H     O O 5,6-di-Cl  209-211                                  180  Br   Br     H     O O 6,7-di-Cl  206-208                                  181  Cl   Cl     H     O O 5,7-di-CH.sub.3,6-Cl                                                                      210-212                                  182  Br   Br     H     O O 5,7-di-CH.sub.3,6-Cl                                                                      219-221                                  183  Cl   CH.sub.3                                                                              H     O O 5,7-di-CH.sub.3,6-Cl                                                                      187-188                                  184  Cl   Cl     H     O O 7,8-di-Cl  212-214                                  185  Br   Br     H     O O 7,8-di-Cl  211-212                                  186  Cl   CH.sub.3                                                                              H     O O 7,8-di-Cl  234-236                                  187  Cl   Cl     H     O O 5,7-di-Br,6-CH.sub.3                                                                      217-218                                  188  Cl   CH.sub.3                                                                              H     O O 5,7-di-Br,6-CH.sub.3                                                                      201-203                                  189  Cl   Cl     H     O O 5,8-di-Cl  190-191                                  190  Br   Br     H     O O 5,8-di-Cl  203-205                                  191  Cl   CH.sub.3                                                                              H     O O 5,8-di-Cl  181-183                                  192  Cl   Cl     H     O O 5-NO.sub.2 211-212                                  __________________________________________________________________________

EXAMPLE 193 Preparation of 4-hydroxy-5-(trifluoromethyl)dithiocoumarin ##STR23##

A mixture of 2'-fluoro-6'-(trifluoromethyl)acetophenone (3.0 g, 14.5 mmol), carbon disulfide (1.5 mL, 26.7 mmol) and dimethylformamide (DMF) (12.5 mL) in benzene at 15°-25° C. is treated portion-wise with a 60% dispersion of sodium hydride in mineral oil (1.15 g, 28.8 mmol NaH) over a 1.5 hour period, stirred for 0.5 hour, heated at 125° C. for 1 hour, cooled to room temperature and diluted with water. The resultant mixture is treated with acetic acid and extracted with ether. The aqueous phase is acidified to pH 3 with HCl and extracted with ethyl acetate. The ethyl acetate extracts are combined, washed sequentially with water and brine, dried over MgSO₄ and concentrated in vacuo to give an orange oil residue. The residue is crystallized from diethyl ether/hexanes to give the title product as a white solid, 3.0 g (79% y), mp 142°-144° C., identified by IR, ¹ HNMR, ¹⁹ FNMR and mass spectral analyses.

EXAMPLE 194 Preparation of 4-(2,6-dichlorophenoxy)-5-trifluoromethyl)dithiocoumarin ##STR24##

Using essentially the same procedures described in Examples 3 and 4 hereinabove, the title product is obtained and identified by IR, ¹ HNMR, ¹⁹ FNMR and mass spectral analyses.

EXAMPLE 195 Preparation of 4-(2,6-dichlorophenoxy)-6-chlorodithiocoumarin ##STR25##

Using essentially the same procedures described hereinabove in Examples 3, 4 and 193, the title product is obtained, mp 208°-210° C., identified by IR, ¹ HNMR and mass spectral analyses.

EXAMPLE 196 Preemergence Herbicidal Evaluation Of Test Compounds In The Presence of Transplanted Rice Under Flooded Paddy Conditions

The preemergence herbicidal activity and rice crop tolerance under post-transplant application conditions is determined in the following manner. Grass weed seeds or tubers are planted in the top 0.5 cm of silt loam soil in plastic containers with no drainage holes and 4-6 rice seedlings (CV. Tebonnet), at the two-leaf stage, are transplanted into the same containers. The plastic containers may be 32 oz. containers having a diameter of 10.5 cm or 13 cm×13 cm square by 8 cm deep. After seeding and transplanting, the containers are placed on greenhouse benches and the soil is kept saturated for 3 days. On the 3rd day, the containers are flooded to a level of 2-3 cm of water above the soil surface. The flooded soil surface is then treated with selected aqueous acetone (20/80 v/v water/acetone) mixtures and sufficient test compound to provide the equivalent of about 4.0 kg/ha to 0.50 kg/ha of active ingredient. After treatment, the containers are kept on greenhouse benches and watered such that the water level is maintained at 2-3 cm above the soil surface.

Three to four weeks after treatment, the plants are evaluated and rated for herbicidal effect based on visual determination of stand, size, vigor, chlorosis, growth malformation and overall appearance. The rating system used is shown below. If more than one test is run, the data are averaged. The results are reported in Table III.

    ______________________________________                                         RATING SYSTEM USED                                                                                      % Control                                             Rating   Meaning         Compared to Check                                     ______________________________________                                         0        No Effect         0                                                   1        Trace Effect     1-5                                                  2        Slight Effect    6-15                                                 3        Moderate Effect 16-29                                                 4        Injury          30-44                                                 5        Definite Injury 45-64                                                 6        Herbicidal Effect                                                                              65-79                                                 7        Good Herbicidal Effect                                                                         80-90                                                 8        Approaching Complete Kill                                                                      91-99                                                 9        Complete Kill    100                                                  --       Not Tested                                                            ______________________________________                                         PLANT SPECIES USED                                                             Abbreviation                                                                               Common Name  Scientific Name                                       ______________________________________                                         ECHCG       Barnyard Grass                                                                              Echinochloa crus-galli                                                         (L.) Beauv.                                           ECHORC      Water Grass  Echinochloa oryzoides                                                          (ARD.) Fritsch                                        ORYSAT      Rice, Tebonnet                                                                              Oryza sativa, L.                                                               CV. Tebonnet                                          ______________________________________                                    

                  TABLE III                                                        ______________________________________                                         PREEMERGENCE/POST-TRANSPLANT EVALUATION                                        Example   Rate                                                                 No.       kg/ha  ECHCG      ECHORC ORYSAT                                      ______________________________________                                         8         2.0    9.0        --     0.0                                                   1.0    9.0        9.0    0.3                                                   0.5    9.0        9.0    0.3                                         9         1.0    9.0        --     1.5                                                   0.5    9.0        --     1.5                                         10        1.0    9.0        9.0    0.0                                                   0.5    9.0        9.0    0.0                                         12        1.0    --         9.0    0.0                                                   0.5    --         8.0    0.0                                         21        1.0    8.0        --     0.0                                                   0.5    7.0        --     0.0                                         22        1.0    9.0        --     0.5                                                   0.5    9.0        --     0.5                                         23        1.0    0.0        --     0.0                                                   0.5    0.0        --     0.0                                         24        1.0    9.0        --     2.0                                                   0.5    9.0        --     2.0                                         25        1.0    --         6.0    0.0                                                   0.5    --         2.0    0.0                                         29        1.0    7.0        --     3.0                                                   0.5    7.0        --     2.0                                         30        1.0    9.0        --     0.5                                                   0.5    9.0        --     0.3                                         31        1.0    9.0        --     0.0                                                   0.5    9.0        --     0.0                                         32        1.0    9.0        --     0.0                                                   0.5    9.0        --     0.0                                         33        1.0    0.0        --     0.0                                                   0.5    0.0        --     0.0                                         34        4.0    9.0        --     0.0                                                   1.0    9.0        9.0    0.0                                                   0.5    9.0        7.0    0.0                                         38        1.0    8.0        --     0.0                                                   0.5    7.0        --     0.0                                         39        1.0    7.0        --     0.0                                                   0.5    7.0        --     0.0                                         40        1.0    9.0        --     0.0                                                   0.5    6.0        --     0.0                                         41        1.0    9.0        --     0.0                                                   0.5    9.0        --     0.0                                         42        1.0    0.0        --     0.0                                                   0.5    0.0        --     0.0                                         43        1.0    8.0        --     1.0                                                   0.5    7.0        --     0.0                                         44        1.0    9.0        --     0.0                                                   0.5    7.0        --     0.0                                         45        1.0    9.0        --     0.0                                                   0.5    9.0        --     0.0                                         46        1.0    1.0        --     0.0                                                   0.5    0.0        --     0.0                                         47        1.0    0.0        --     0.0                                                   0.5    0.0        --     0.0                                         48        1.0    0.0        --     0.0                                                   0.5    0.0        --     0.0                                         49        1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         50        1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         51        1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         52        4.0    3.0        --     0.0                                                   1.0    7.0        0.0    0.0                                                   0.5    2.0        0.0    0.0                                         53        4.0    0.0        --     0.0                                                   1.0    2.0        --     0.0                                                   0.5    1.0        --     0.0                                         54        1.0    0.0        --     0.0                                                   0.5    0.0        --     0.0                                         55        1.0    9.0        9.0    0.0                                                   0.5    9.0        9.0    0.0                                         56        1.0    9.0        --     0.0                                                   0.5    8.0        --     0.0                                         57        1.0    9.0        --     0.0                                                   0.5    9.0        --     0.0                                         58        1.0    9.0        --     0.0                                                   0.5    9.0        --     0.0                                         59        1.0    0.0        --     0.0                                                   0.5    0.0        --     0.0                                         60        1.0    9.0        --     0.0                                                   0.5    9.0        --     0.0                                         61        1.0    2.0        --     0.0                                                   0.5    1.0        --     0.0                                         62        1.0    0.0        --     0.0                                                   0.5    0.0        --     0.0                                         63        1.0    9.0        --     0.0                                                   0.5    9.0        --     0.0                                         64        1.0    0.0        --     0.0                                                   0.5    0.0        --     0.0                                         65        1.0    9.0        9.0    0.0                                                   0.5    9.0        9.0    0.0                                         66        1.0    7.0        --     0.0                                                   0.5    1.0        --     0.0                                         67        1.0    9.0        --     0.0                                                   0.5    6.0        --     0.0                                         68        1.0    0.0        --     0.0                                                   0.5    0.0        --     0.0                                         69        1.0    9.0        --     0.0                                                   0.5    9.0        --     0.0                                         70        1.0    9.0        --     0.0                                                   0.5    9.0        --     0.0                                         71        1.0    0.0        --     0.0                                                   0.5    0.0        --     0.0                                         72        1.0    9.0        --     0.0                                                   0.5    9.0        --     0.0                                         73        1.0    0.0        --     0.0                                                   0.5    0.0        --     0.0                                         74        1.0    9.0        --     0.0                                                   0.5    9.0        --     0.0                                         75        1.0    0.0        --     0.0                                                   0.5    0.0        --     0.0                                         76        1.0    4.0        --     0.0                                                   0.5    2.0        --     0.0                                         77        1.0    0.0        --     0.0                                                   0.5    0.0        --     0.0                                         78        1.0    --         0.0    0.0                                                   0.5    --         0.0    0.0                                         79        1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         80        1.0    --         0.0    0.0                                                   0.5    --         0.0    0.0                                         81        1.0    --         0.0    0.0                                                   0.5    --         0.0    0.0                                         82        1.0    --         9.0    0.0                                                   0.5    --         8.0    0.0                                         83        1.0    --         0.0    0.0                                                   0.5    --         0.0    0.0                                         84        1.0    --         6.0    0.0                                                   0.5    --         1.0    0.0                                         85        1.0    9.0        --     0.0                                                   0.5    9.0        --     0.0                                         86        1.0    9.0        9.0    0.0                                                   0.5    9.0        9.0    0.0                                         87        4.0    9.0        --     0.0                                                   1.0    9.0        9.0    0.0                                                   0.5    9.0        9.0    0.0                                         88        1.0    7.0        --     0.0                                                   0.5    6.0        --     0.0                                         89        1.0    6.0        --     0.0                                                   0.5    6.0        --     0.0                                         90        1.0    4.5        --     0.0                                                   0.5    3.5        --     0.0                                         91        1.0    9.0        --     0.0                                                   0.5    9.0        --     0.0                                         92        1.0    2.0        --     0.0                                                   0.5    2.0        --     0.0                                         93        1.0    9.0        --     0.0                                                   0.5    9.0        9.0    0.0                                         94        1.0    9.0        --     0.0                                                   0.5    9.0        9.0    0.0                                         95        1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         101       1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         110       1.0    --         8.5    0.0                                                   0.5    --         8.0    0.0                                         111       1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         114       2.0    --         0.0    0.0                                                   1.0    --         0.0    0.0                                                   0.5    --         0.0    0.0                                         116       1.0    --         5.5    0.0                                                   0.5    --         1.5    0.0                                         117       2.0    --         7.0    4.0                                                   1.0    --         7.0    3.0                                                   0.5    --         3.0    0.5                                         121       1.0    --         9.0    2.0                                                   0.5    --         9.0    1.0                                         122       1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         127       1.0    --         0.0    0.0                                                   0.5    --         0.0    0.0                                         133       1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         136       1.0    --         9.0    0.0                                                   0.5    --         9.0    0.5                                         137       1.0    --         9.0    0.0                                                   0.5    --         9.0    0.2                                         138       2.0    --         9.0    4.0                                                   1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         139       1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         148       1.0    --         0.0    0.0                                                   0.5    --         0.0    0.0                                         155       1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         156       1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         157       1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         172       1.0    --         9.0    0.0                                                   0.5    --         8.5    0.0                                         173       1.0    --         8.0    0.0                                                   0.5    --         8.0    0.0                                         174       1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         175       1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         176       1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         177       1.0    --         7.0    0.0                                                   0.5    --         5.5    0.0                                         192       1.0    --         9.0    0.0                                                   0.5    --         9.0    0.0                                         ______________________________________                                    

EXAMPLE 197 Preemergence Herbicidal Evaluation Of Test Compounds In The Presence Of Transplanted Rice Under Flooded Paddy Conditions

In this example, Deluvian paddy soil (Toyokawa paddy soil) is placed in plastic pots, 100 cm² ×9 cm in depth. Water is added to the level of the soil surface in the pot and the mixture is paddled 3 cm in depth.

Pots are then variously sown with monocotyledenous weed seeds and tubers at 0-2 cm in soil depth, as well as transplanted rice plants at the 2.5 leaf stage. The rice plants are transplanted at about 3 cm soil depth. Water is then added to all of the pots to 3 cm deep and kept at a depth of 3 cm for the duration of the test. Test compounds are applied in the manner described in Example 96 two days after transplanting the rice plants and sowing the weed seeds and tubers. The pots are then placed on greenhouse benches and cared for in the conventional manner. Tests are evaluated at 20 and 30 days after treatment. Evaluations made at 30 days after treatment are shown on Table IV. The rating system used is the same as that described in Example 196.

    ______________________________________                                         PLANT SPECIES USED                                                             Abbreviation                                                                              Common Name    Scientific Name                                      ______________________________________                                         ECHCG      Barnyard Grass Echinochloa crus-galli                               SAGPY      Arrowhead (Pygmaea)                                                                           Sagittaria pyamaea                                   CYPSE      Flatsedge,     Cyperus serotinus                                               perennial                                                           MOOVA      Monochoria     Monochoria vaginalis                                 CYPDI      Flatsedge,                                                                     smallflower    Cyperus difformis                                    SCPJU      Bulrush, Japanese                                                                             Scirpus juncoides                                    ORYSAK     Rice, Koshihikari                                                                             Oryza sativa, L.                                                               cv. Koshihikari                                      ______________________________________                                    

                                      TABLE IV                                     __________________________________________________________________________     PREEMERGENCE/POST-TRANSPLANT EVALUATION                                        Ex. Rate                                                                       No. kg/ha                                                                             ECHCG                                                                              SAGPY                                                                              CYPSE                                                                              MOOVA                                                                               CYPDI                                                                              SCPJU                                                                              ORYSAK                                         __________________________________________________________________________      8  1.0                                                                               9   2   2   9    9   8   0                                                  0.5                                                                               9   1   0   9    9   7   0                                               9  1.0                                                                               7   0   0   1    2   0   0                                                  0.5                                                                               6   0   0   0    0   0   0                                              10  1.0                                                                               9   2   0   9    9   5   0                                                  0.5                                                                               9   0   0   8    9   4   0                                              12  1.0                                                                               9   0   0   7    3   0   0                                                  0.5                                                                               9   0   0   6    2   0   0                                              21  1.0                                                                               8   0   7   3    5   0   0                                                  0.5                                                                               7   0   2   0    3   0   0                                              22  1.0                                                                               9   1   1   9    8   7   0                                                  0.5                                                                               9   0   0   8    7   5   0                                              23  2.0                                                                               9   0   0   3    2   2   0                                                  1.0                                                                               6   0   0   0    0   0   0                                                  0.5                                                                               4   0   0   0    0   0   0                                              25  1.0                                                                               9   0   0   9    6   3   0                                                  0.5                                                                               9   0   0   8    3   0   0                                              31  1.0                                                                               9   0   4   7    7   3   0                                                  0.5                                                                               9   0   0   7    6   0   0                                              32  1.0                                                                               9   0   2   8    8   2   0                                                  0.5                                                                               9   0   1   7    7   0   0                                              33  2.0                                                                               6   9   9   9    9   7   8                                                  1.0                                                                               4   8   9   9    9   6   8                                                  0.5                                                                               2   7   9   9    8   5   5                                              35  2.0                                                                               8   2   0   0    1   0   0                                                  1.0                                                                               8   0   0   0    0   0   0                                                  0.5                                                                               7   0   0   0    0   0   0                                              38  1.0                                                                               8   0   0   0    0   0   0                                                  0.5                                                                               6   0   0   0    0   0   0                                              39  1.0                                                                               7   0   0   0    0   0   0                                                  0.5                                                                               5   0   0   0    0   0   0                                              40  1.0                                                                               9   0   0   0    0   0   0                                                  0.5                                                                               9   0   0   0    0   0   0                                              41  1.0                                                                               9   1   7   8    9   2   1                                                  0.5                                                                               9   0   3   7    7   1   0                                              42  2.0                                                                               2   0   0   0    0   0   0                                                  1.0                                                                               0   0   0   0    0   0   0                                                  0.5                                                                               0   0   0   0    0   0   0                                              43  1.0                                                                               8   0   0   0    0   0   0                                                  0.5                                                                               6   0   0   0    0   0   0                                              44  1.0                                                                               8   0   0   0    0   0   0                                                  0.5                                                                               5   0   0   0    0   0   0                                              45  1.0                                                                               7   0   0   0    0   0   0                                                  0  4   0   0   0    0   0   0                                              46  2.0                                                                               0   0   0   0    0   0   0                                                  1.0                                                                               0   0   0   0    0   0   0                                              47  2.0                                                                               0   0   0   0    0   0   0                                                  1.0                                                                               0   0   0   0    0   0   0                                              48  2.0                                                                               0   0   0   0    0   0   0                                                  1.0                                                                               0   0   0   0    0   0   0                                              49  1.0                                                                               9   0   5   9    9   8   0                                                  0.5                                                                               9   0   2   9    8   5   0                                              50  1.0                                                                               9   0   0   8    8   1   0                                                  0.5                                                                               9   0   0   8    7   0   0                                              51  1.0                                                                               9   0   2   8    7   0   0                                                  0.5                                                                               8   0   0   8    5   0   0                                              55  1.0                                                                               9   1   9   9    9   9   0                                                  0.5                                                                               9   0   8   9    9   8   0                                              56  1.0                                                                               8   0   0   3    2   0   0                                                  0.5                                                                               6   0   0   2    1   0   0                                              57  1.0                                                                               9   0   2   2    2   0   0                                                  0.5                                                                               9   0   0   1    1   0   0                                              58  1.0                                                                               9   0   0   4    3   0   0                                                  0.5                                                                               9   0   0   2    1   0   0                                              59  1.0                                                                               5   0   0   1    2   2   0                                                  0.5                                                                               3   0   0   0    0   0   0                                              60  1.0                                                                               9   0   0   6    5   0   0                                                  0.5                                                                               9   0   0   5    3   0   0                                              61  1.0                                                                               4   0   0   1    1   0   0                                                  0.5                                                                               3   0   0   0    0   0   0                                              62  1.0                                                                               2   0   0   0    0   0   0                                                  0.5                                                                               0   0   0   0    0   0   0                                              63  1.0                                                                               9   0   0   2    1   1   0                                                  0.5                                                                               9   0   0   1    0   0   0                                              64  1.0                                                                               1   0   0   0    0   0   0                                                  0.5                                                                               0   0   0   0    0   0   0                                              65  1.0                                                                               9   4   5   9    9   2   1                                                  0.5                                                                               9   2   2   9    9   1   0                                              66  1.0                                                                               9   0   0   2    2   0   0                                                  0.5                                                                               8   0   0   0    0   0   0                                              67  1.0                                                                               9   0   1   2    3   0   1                                                  0.5                                                                               8   0   0   0    2   0   0                                              68  1.0                                                                               0   0   0   0    0   0   0                                                  0.5                                                                               0   0   0   0    0   0   0                                              69  1.0                                                                               9   0   2   7    7   2   1                                                  0.5                                                                               9   0   0   6    6   0   0                                              70  1.0                                                                               9   0   5   2    1   0   0                                                  0.5                                                                               9   0   0   0    0   0   0                                              71  1.0                                                                               6   0   0   0    0   0   0                                                  0.5                                                                               5   0   0   0    0   0   0                                              72  1.0                                                                               9   0   1   7    4   0   0                                                  0.5                                                                               9   0   0   3    2   0   0                                              73  1.0                                                                               7   0   2   0    0   0   0                                                  0.5                                                                               3   0   0   0    0   0   0                                              74  1.0.                                                                              9   0   0   4    6   2   0                                                  0.s                                                                               9   0   0   2    3   0   0                                              75  1.0                                                                               4   0   0   2    1   0   0                                                  0.5                                                                               2   0   0   0    0   0   0                                              76  1.0                                                                               7   0   0   2    1   1   0                                                  0.5                                                                               6   0   0   0    0   0   0                                              77  1.0                                                                               6   0   0   2    0   0   0                                                  0.5                                                                               6   0   0   1    0   0   0                                              78  1.0                                                                               2   1   4   2    0   6   0                                                  0.5                                                                               0   0   2   1    0   4   0                                              79  1.0                                                                               9   2   0   9    9   7   0                                                  0.5                                                                               9   1   0   8    7   6   0                                              85  1.0                                                                               9   0   0   4    4   2   0                                                  0.5                                                                               7   0   0   1    2   1   0                                              86  1.0                                                                               9   5   5   9    9   9   0                                                  0.5                                                                               9   2   2   9    9   8   0                                              87  1.0                                                                               9   0   4   8    8   4   0                                                  0.5                                                                               9   0   2   7    8   2   0                                              88  1.0                                                                               5   0   0   0    0   0   0                                                  0.5                                                                               4   0   0   0    0   0   0                                              89  1.0                                                                               4   0   0   0    0   0   0                                                  0.5                                                                               2   0   0   0    0   0   0                                              90  1.0                                                                               3   0   0   0    0   0   0                                                  0.5                                                                               0   0   0   0    0   0   0                                              91  1.0                                                                               9   0   0   5    8   0   0                                                  0.5                                                                               9   0   0   3    5   0   0                                              93  1.0                                                                               9   0   2   9    9   7   0                                                  0.5                                                                               9   0   0   8    8   5   0                                              94  1.0                                                                               9   0   7   9    9   8   0                                                  0.5                                                                               9   0   3   9    9   5   0                                              116 0.50                                                                              7   6   3   2    8   6   0                                                  0.25                                                                              5   4   1   0    7   5   0                                              117 0.50                                                                              7   2   5   4    8   7   1                                                  0.25                                                                              5   1   2   0    7   6   1                                              119 0.50                                                                              9   2   0   0    2   0   0                                                  0.25                                                                              8   0   0   0    1   0   0                                              120 0.50                                                                              9   0   --  6    9   8   0                                                  0.25                                                                              9   0   --  2    9   7   0                                              121 0.50                                                                              9   0   3   5    9   8   0                                                  0.25                                                                              9   0   0   2    9   6   0                                              122 0.50                                                                              9   4   0   0    9   5   0                                                  0.25                                                                              9   2   0   0    9   3   0                                              123 0.50                                                                              9   0   0   0    9   7   0                                                  0.25                                                                              9   0   0   0    7   5   0                                              124 0.50                                                                              9   2   0   0    9   7   0                                                  0.25                                                                              9   0   0   0    9   6   0                                              125 0.50                                                                              9   0   2   5    9   9   0                                                  0.25                                                                              9   0   0   2    9   6   0                                              126 0.50                                                                              9   2   --  3    7   6   0                                                  0.25                                                                              9   2   --  2    3   2   0                                              136 0.59                                                                              9   0   0   2    7   5   0                                                  0.25                                                                              9   0   0   0    6   4   0                                              137 0.50                                                                              9   0   2   7    9   9   0                                                  0.25                                                                              9   0   1   7    9   9   0                                              138 0.50                                                                              9   0   0   5    9   9   0                                                  0.25                                                                              9   0   0   6    9   9   0                                              139 0.50                                                                              9   0   2   8    9   9   0                                                  0.25                                                                              9   0   2   8    9   9   0                                              155 0.50                                                                              9   0   2   9    9   9   0                                                  0.25                                                                              9   0   --  7    9   9   0                                              __________________________________________________________________________ 

What is claimed is:
 1. A method for the control of monocotyledenous annual, perennial and aquatic plant species which comprises applying to the soil or water containing seeds or other propagating organs thereof a herbicidally effective amount of a compound of formula I ##STR26## wherein X and X' are each independently halogen, C₁ -C₄ alkyl or C₂ -C₄ alkenyl;W, Y and Z are each independently O or S; R is any combination of from one to three H, halogen, C₁ -C₄ alkyl, C₃ -C₆ cycloalkyl, C₁ -C₄ haloalkyl or C₁ -C₄ alkoxy groups; R₁ is any combination of from one to four H, halogen, OH, CN, NO₂, SH, C₁ -C₆ alkyl optionally substituted with one or more halogen or OR₂ groups, C₃ -C₆ cycloalkyl, C₁ -C₆ alkylthio, C₂ -C₆ alkenyl, C₂ -C₆ haloalkenyl, C₂ -C₆ alkynyl, C₂ -C₆ haloalkynyl, OR₂, OCH₂ COOR₃, OCH₂ OR₄, OCOOR₅, OCONHR₆, OCOR₇, S(O)_(n) R₈, COR₉, CH(OR₁₀)₂, phenyl optionally substituted with one to three halogen, CN, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups, or benzyl optionally substituted with one to three halogen, CN, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl or C₁ -C₄ alkoxy groups with the proviso that at least one of R₁ must be NO₂, C₁ -C₆ thioalkyl or COOH; R₂ is H, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₂ -C₆ alkenyl, C₂ -C₆ alkynyl, C₂ -C₆ haloalkenyl or C₂ -C₆ haloalkynyl; R₃, R₄, R₅, R₆ and R₇ are each independently H, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₃ -C₆ cycloalkyl, phenyl optionally substituted with one to three halogen, CN, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups, or benzyl optionally substituted with one to three halogen, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl or C₁ -C₄ alkoxy groups; R₈ is C₁ -C₄ alkyl, C₁ -C₄ haloalkyl or phenyl optionally substituted with one to three halogen, CN, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups; R₉ is H, OH, C₁ -C₄ alkyl, C₁ -C₄ alkoxy, phenyl optionally substituted with one to three halogen, CN, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups, benzyl optionally substituted with one to three halogen, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups or NR₁₁ R₁₂ ; R₁₀ is H, C₁ -C₄ alkyl or --(CH₂)_(m) --; R₁₁ and R₁₂ are each independently H, C₁ -C₄ alkyl, C₂ -C₄ alkenyl or R₁₁ and R₁₂ may be taken together with the atoms to which they are attached to form a 5- or 6-membered ring optionally interrupted by oxygen; n is an integer of 0, 1 or 2 and m is an integer of 2 or
 3. 2. The method according to claim 1 having a formula I compound wherein X and X' are each independently Cl, Br or CH₃ and W and, Y are O.
 3. The method according to claim 2 having a formula I compound wherein R is H and R₁ is one, two or three halogen, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy, C₁ -C₄ haloalkoxy or NO₂ groups, with the proviso that R₁ is at least one NO₂ group.
 4. The method according to claim 3 having a formula I compound wherein X and X' are Cl, Br or CH₃ ; R is H and R₁ is 5-NO₂.
 5. A method for the selective control of monocotyledenous weeds in the presence of a crop plant which comprises applying to the soil or water in which the seeds or propagating organs of said weeds are located and in which the crop plant has been planted or transplanted a herbicidally effective amount of a compound of formula I ##STR27## wherein X, X', W, Y, Z, R and R₁ are as defined in claim
 1. 6. The method according to claim 5, wherein the crop is a cereal crop.
 7. The method according to claim 6 wherein the cereal crop is wheat, oat, barley, rye, rice or corn.
 8. The method according to claim 7 wherein the cereal crop is rice.
 9. The method according to claim 8 wherein the monocotyledenous weed is a grass weed.
 10. The method according to claim 8 wherein the formula I compound is applied at a rate of about 4.0 kg/ha to 0.06 kg/ha.
 11. The method according to claim 10 wherein the formula I compound is applied at a rate of about 2.0 kg/ha to 0.06 kg/ha.
 12. The method according to claim 3 wherein the formula I compound is 4-(2,6-dichlorophenoxy)-5-nitrocoumarin.
 13. The method according to claim 10 wherein the formula I compound is 4-(2,6-dichlorophenoxy)-5-nitrocoumarin. 